3rdBird

iTrader: (1)

Well, everything with my car is new. New high compression 406 engine, TH400 trans w/ 5500 stall converter & Moser 12 bolt w/ 373.
We 're finally getting this thing dialed in & I was playing around & found it wants to break the tires at 2200 ish RPM's
It doesnt look like it wants to evne come close to stalling at anything close to 3000.
Any ideas?

AlkyIROC

The only way to know a converters true stall speed is with a tranny brake. How much a converter stalls depends on how much torque is put into it. The same converter behind different engines will stall at different rpms.

That's a pretty high stall converter and not much gearing to go with it. What's the camshafts total duration? Not the .050" duration.

3rdBird

iTrader: (1)

I'll post the cam info tomarrow, I dont know it off the top of my head.
We're looking to spray it off the line, so 373 seamed to be a good starting point. we didnt want to leave at 4000ish RPM's & have to shift right away @ 7000 rpms. Maybe Powerglide is on the future??

3rdBird

iTrader: (1)

312-322 @ 20, & 282 @ 50, 630 lift..

mw66nova

iTrader: (13)

that stall speed is the flash speed. the closest you'll get to it without a trans brake is to go down the road (at a slow-ish rate of speed) in 1:1 (third, second, whichever it is for you) and jump on the gas, whatever the rpm's flash to is close to what the actual stall rating will be. you'll never be able to get the "true" stall speed out of just doing a powerbrake style burnout, the tires will spin because of the torque multiplications overpowering the brakes.

AlkyIROC

OK, so 312/322 total duration. That's pretty aggressive. Looks like it has an operating range somewhere around 4500-7500

No excuse why it breaks the tires loose at such a low rpm. My converter stalls at 6000 and I can hold the car with the brakes somewhere in the 3000 range. As I previously stated, you won't know the true stall without a transbrake and will never see true stall using the vehicle's brakes to try and hold the car.

A playback tach can help. I launch at 4500 rpm. The tach shows the rpm quickly jumps to 6000 once the transbrake is released then climbs as I start moving down the track. Trying to watch a tach and launch at WOT is just too fast. The playback tach can play back at 1/3 speed so you can watch after a run and see things happen slower.

http://videos.streetfire.net/video/8...008_168661.htm

You can see in this video how a WOT launch can show stall speed or at least flash speed. I turn on the tach recorder just before I hit the prestage beams. My throttle linkage moved and I rolled into the beams at 3500. As soon as I activated the delay box, the 2 step held the engine at 5000 rpm to launch. When the transbrake released, you can see the tach jump to just over 6000 and stay there briefly before it started to climb. Footbrake launching will be harder to see but the tach should still jump up to the stall speed providing you don't have any wheel spin to make it go higher. That's a big problem when trying to see flash speed when launching.

There isn't going to be any easier way to see what kind of stall speed your converter has. You just can't check it properly with the vehicles brakes.

Your 3.73 gears will be killing you. That cam and converter will want a deep gear. 4.56 or deeper depending on your tire size.

The problem with trying to see flash speed while driving is normally a transmission will downshift when you go to WOT while driving. This will artificially increase the rpm. A manual valve body that will stay in high gear will work. Somehow I doubt a car with a camshaft like that and a 5500 stall converter will see much street use.

3rdBird

iTrader: (1)

The engine is 13.75-1 CR, the car is being built for drag only, I know the gears are kinda wimpy, but as I said we're looking to spray it off the line. My engine builder was leaning towards a 456 gear, & the D&P Converters said they'de re-stall my converter as no charge.
I've had a good month at the shop, so I might just send the TH400 out & have a Transbrake installed...maybe I should do the trans brake first before sending the converter back..??

1BADRZ28

iTrader: (2)

I'd send the converter back and have it calibrated for nitrous use. Otherwise, you will probbaly be blowing through the converter at the end of the track. A trans brake will help also. I have a 406,4.11's, and a 28" tall tire and come through the traps at 7400 rpm on the nitrous..

1TUF92Z

No way that TC will blow up for what we're intending to use it for. Something else will brake before the TC gives.

JesasaurusRex

iTrader: (3)

, and i don't know if that's for the way you used the word brake or for the fact that you think he ment blow up when he said blow through

1BADRZ28

iTrader: (2)

Yes, blow through not up.

mw66nova

iTrader: (13)

note to self, stay outta elk grove, CA...

automec

i run a 274-282 cam @ .050 with a jw converter and brake, and 4.11 gears. foot brake i can only hold it to 2200 rpm. but on the transbrake it stalls at 5400rpm.

3rdBird

iTrader: (1)

Checking into a transbrake as we speak.

AlkyIROC

Transbrake launches are so much better than footbrake. Make sure the rest of the driveline can handle the shock of a transbrake launch. The 12 bolt will be fine. Driveshaft should have 1350 u-joints.

Transbrakes for the TH400 are cheaper than ones for a TH350 but not as cheap as ones for a powerglide. Internal modifications need to be done to the tranny so it will need to be removed and stripped done to put in the transbrake. It not just a simple valve body swap.

3rdBird

iTrader: (1)

I cant wait!!

Burgundy Bomber

Where can i find a transbrake for my th-350? i'm still debating on which slapstick to get, i'm sure i'm going with a 3800, 4k stall this time.

TraviZ

iTrader: (2)

Marc, when you going out for the first time? maybe we can make a date. hows megasquirt running?

Fast 383

iTrader: (2)

I have brakes here for all of the above transmissions mentioned on the shelf. I can offer them at discounts as well. Not trying to sell product but trying to help out thirgen members. You can PM me if interested. I work for Transmission Specialties.

3rdBird

iTrader: (1)

Thanks for your input, have you heard anything on the "Griner" valve body? A builder here in town swears by them.

Travis I havent had a chance to take it out, I'm either sick, or its raining. The MegaSquirt is alot more complex than I 'd rather have now, it seems like its more tailored to street applications (according to Bennie). We just need it to idle & the flip the switch to dump fuel.
If we dont get it figured out soon, I'm gonna scrap it & go Accel Gen 6 or 7.

xpndbl3

iTrader: (5)

how much is a TH400 brake ?

TraviZ

iTrader: (2)

maybe try alpha-n isntead of map sensing. that way is much more suited to what you just said.
ask benny bout it. alpha-n is a TPS by RPM table where you input a KPA reading instead of VE tables. then you just need to make a VE table for your KPA readings.

Fast 383

iTrader: (2)

$299 shipped


http://transmission-specialties.com/...roducts_id=370

xpndbl3

iTrader: (5)

hmmm is this something i can install myself with the trans out of the car or should i really let a trans guy handle this. if i can't do it myself what's the average TB install rate these days? i got a fresh TH400 with no miles on it that I wouldn't mind tossing one into.

Fast 383

iTrader: (2)

IT's not something I would reccomend if you have never been into a trans before. Possibly a Powerglide because they are simpler but a 400 has to come apart to install the springs into the drum. If you are brave it does come with good instructions and my transmission builder will answer your questions one by one if need be. If you are interested I can do a search of your area to see where the good trans shops that we deal with are so you could drop it off and have them do it with no problem. Pm me with a couple of your close by zip codes and cities if your interested.

xpndbl3

iTrader: (5)

PM sent.

AlkyIROC

These are the basic installation instructions for a TH400 transbrake. The type of internal modifications from brand to brand are very close to the same.

http://store.summitracing.com/instru...2D221500%2Epdf

3rdBird

iTrader: (1)

Who makes it? TS? Any info on the Griner? Its supposed to be a billet body, etc etc. Just wanted some more intake on it.

Fast 383

iTrader: (2)

I would not be able to provide you any useful info on another manufacturer such as Griner. My company makes the T-400 Trans brake V/B's and manual V/B's as well here in our shop. We put them in our Failsafe T-400's rated to 2000HP. I also have plenty of customer that I personally know locally running them well into the low 8's. They are
Pro-tree style brakes which means the brake will need to be activated while the shifter selecter is in Neutral for the vehicle to go in Reverse. Pro-Tree style brakes are among the fastest available.

Burgundy Bomber

I've been looking into *******(a banned word, business name) performance manual valve body and trans brake, supposedly they make some really wicked stalls as well,
I'm interested in a PM about trans brakes and manual valve bodies if you make them....

3rdBird

iTrader: (1)

Hmmmmm. I'll consider it. My delima is the builder is sold on Griner & he's the one installing it & backing its performance & warranty. Pro tree sounds like the way to go.

TraviZ

iTrader: (2)

marc, off topic, but did you look into alpha-n? im actually using it now on my iroc for idling and low rpm cruising up to around 2600rpm. its definitely working for me! tell benny get on it, dont give up.

3rdBird

iTrader: (1)

Bennie & his wife just had a kid, so he's a little preoccupied. We'll try it when we get back.

TraviZ

iTrader: (2)

dont let a kid get in the way of racing!

Shagwell

You will not be diss-appointed with a griner brake. JW and ATI both have versions of it out now as well. It's a billet chunk with the appropriate passageways and the selector valve. Specifically built for racing, not just a modified stock vb.

Although I have had no release issue with my "pro-tree" brake I hate the thing when moving the car around. Manual rack + steering wheel button = frustration.

3rdBird

iTrader: (1)

3rdBird

iTrader: (1)

Isnt there an On/Off switch that has to be thrown when the vehicle is in nuetral before the brake can be "live"?

superT

iTrader: (1)

dude you can't be married!!!!!!!!!!!!!!!!!!! or you don't have kids one of the two. i mean not to affend but since i've had kids racing my car doesn't make the budget to often and i make about 45,000 a year and my wife makes about 15,000 ballpark. not that i'm proud of it though

TraviZ

iTrader: (2)

feed them top ramen. thats good nuff.

Shagwell

I guess you could wire in a switch if you wanted. I just have the push button on the wheel that activates the t-brake. To back the car up, you have to be in the nuetral or rev position on the shifter and activate the brake. - I have no issues with activating it by accident if that's what you mean, just having to turn the wheel 2-3 turns over itself to turn when backing out means letting go of the button, re-activating, letting go again, etc.

I haven't noticed this brake to be any quicker than the BTE in my other trans, which still has reverse in the shift position. - When I build the trans for the new blower motor it will have aluminum clutch drums with the 300M shafts and the griner style brake. I also like TCI's "pro-x" roller bearing tailhousing, might splurge there as well.